Modifying a stereo solid state guitar amp to have higher wattage power amps

[Dan-Ibanez]

Hello all, been reading some posts but have not found what I'm looking for yet (maybe I'm so new to the field that I don't know how to find it).

I have a few stereo guitar amplifiers that are solid state. They are 65Wx2, 75Wx2, etc. The schematics show the power amps in a triangle after the effects return as if they're in a magical black box... but I know that on the actual circuitry they're not necessarily segregated from the rest of the amp.

Is it possible to modify them to be 100Wx2 or the like? I know that I can take the effects out of the preamp and use a PA power amp, and I know that I can just buy a more powerful guitar amp. There's some sentimental value to these, well, except for one, that I'm more than happy to cut up to learn.

Thanks!
Dan

[The Dude]

It's not normally a simple task. There are rare instances when amp modules can be swapped or boards were masked for additional parts. The problem with that can be that the power supply is not capable of delivering the extra current. At any rate, the audible difference between 75W & 100W would be negligible and probably not worth the effort.

Edit: Can you upload model/schematic information? That would give us a better idea of what we are dealing with.

[loudthud]

There is no practical way to accomplish what you want without rebuilding the amp from the ground up. First you need a new power supply, transformer and filter caps. Next you build the two power amps, and you will most likely need new speakers. Then you must improvise a way to power the old preamp from the new power supply. Unless you have years of experience doing this sort of thing, your chances of success are about zero. You may learn something by trying, but you won't end up with a working guitar amp and there will be a hole in your wallet.

[Dan-Ibanez]

Well I have plenty of current holes in my wallet, so it sounds like this is a pass. Thanks for the insight!

[glebert]

There are some who have bought class D power amp modules that just need a +/- power supply rail and a line level input and can usually get more output power than a BJT or FET output section due to higher efficiency. Search on here for IRS2092. The modules can be had cheap on ebay. I have tried it with a basket case Randall head but got some sort of oscillation and set it aside.

[glebert]

This thread is the one that I was thinking (starting at about post #23). There are also many stereo class D modules available. https://music-electronics-forum.com/...hlight=IRS2092